Recent content by HHOboy

Sorry guys I had to work last night and this morning but now I have some free time. I put a 1MΩ resistor between the input of the opamp and ground as suggested and that has done the trick! Also I removed the 10kΩ resistor that you guys said was unnecessary and that seems fine as well. I...

Ok guys another question regarding this circuit. I am trying to use an oscillator circuit that I made in order to control the current source. The oscillator works fine but produces a signal with a DC offset, and the final output needs to be completely AC. In order to remove the offset I placed a...

Hey Jim! I just got the circuit together and it is working great with an analog potentiometer and I expect it to work just as well with the digital potentiometer because it will not be in rheostat mode. I wanted to thank you for all of you and everyone else for all the help. I would consider...

Hey Jim, saw your last reply after I finished writing mine, I will look for some LM324's I thought that I have some on hand and will begin prototyping it and let you know what happens.

Hey Jim, Thanks for the reply, I wasn't planning on having any negative voltages available but there is a possibility that I could. I like the op-amp design and will try prototyping it and see what I can do. I think that I will give up on trying to use the digital pot as a rheostat with the...

Hey guys, I have been trying to design a constant current source that has a digitally controllable (μcontroller) range of maximum current outputs. Ideally the source would be able to be adjusted from .25mA to 2mA. The input voltage for the source would be in the range of 9 to 14 volts. Also I...

Well this definitely makes much more since now and you are right I was trying to explain why you needed the diode and what would happen without it and looking back I can see that Jim was talking about what would happen without the diode. I didn't mean to be disrespectful and in fact I think I...

OK so if you don't calculate it using Faraday's law, what is Faraday's law used for? And can you give me some link where someone is actually doing these voltage calculations your way? Also if the back EMF is so insignificant why do good engineers even bother adding a flyback diode to protect...

If you scroll down on the page you just linked you will see : "When a magnet is moved into a coil of wire, changing the magnetic field and magnetic flux through the coil, a voltage will be generated in the coil according to Faraday's Law." No where does it show voltage calculations like the...

Again I think you need to brush up on your Lenz's law... It just defines the direction of current it does NOT state that the Voltage will be the necessary voltage to try to sustain the original. Faraday's law defines the voltage in this situation which is very large.

Lenz's law just proves the direction of current. Faraday's law is used to find voltage which is the following equation V= -N * (Δ\Phi / Δt) Using this equation the time will be a couple of microseconds and N (number of loops) will be in the hundreds (for a DC motor). I'm not totally sure...

I see what you are saying and I guess that the voltages are all relative and when the switch is open there isn't a common voltage to work off of except the 24V. The second example still is a bit confusing to me I can definitely see that depending on which way the motor was turning before being...

Hmm... Well you are definitely right about your first example... but it is only true when the two supplies are grounded. When the supplies are not commonly grounded there isn't a way for any current to flow. For example you have 2 completely isolated supplies connecting their output voltages...

Sometimes these diodes are called clamp diodes, and yes you are correct, in the first illustration a large negative voltage is created when the switch is opened. The clamp diode is normally reversed biased but when there is an opposite current flowing it will protect the power supply as well as...

OK well Vcc should denote the operating voltage of the chip, if you want to attach an analong input I would just place it on one of the ATLM pins, for example if you have a potentiometer you would connect one outside pin to the 3.3V connector, and the other outside pin to ground and then the...